Peter K. Wagner

Human sleep under the influence of pulsed radiofrequency electromagnetic fields: A polysomnographic study using standardized conditions

To investigate the influence of radiofrequency electromagnetic fields (EMFs) of cellular phone GSM signals on human sleep electroencephalographic (EEG) pattern, all-night polysomnographies of 24 healthy male subjects were recorded, both with and without exposure to a circular polarized EMF (900 MHz, pulsed with a frequency of 217 Hz, pulse width 577 micros, power flux density 0.2 W/m2. Suppression of rapid eye movement (REM) sleep as well as a sleep-inducing effect under field exposure did not reach statistical significance, so that previous results indicating alterations of these sleep parameters could not be replicated. Spectral power analysis also did not reveal any alterations of the EEG rhythms during EMF exposure. The failure to confirm our previous results might be due to dose-dependent effects of the EMF on the human sleep profile.

Effects of Pulsed High-Frequency Electromagnetic Fields on the Neuroendocrine System

The influence of pulsed high-frequency electromagnetic fields emitted from a circularly polarized antenna on the neuroendocrine system in healthy humans was investigated (900 MHz electromagnetic field, pulsed with 217 Hz, average power density 0.02 mW/cm2). Nocturnal hormone profiles of growth hormone (GH), cortisol, luteinizing hormone (LH) and melatonin were determined under polysomnographic control. An alteration in the hypothalamo-pituitary-adrenal axis activity was found with a slight, transient elevation in the cortisol serum level immediately after onset of field exposure which persisted for 1 h. For GH, LH and melatonin, no significant effects were found under exposure to the field compared to the placebo condition, regarding both total hormone production during the entire night and dynamic characteristics of the secretion pattern. Also the evaluation of the sleep EEG data revealed no significant alterations under field exposure, although there was a trend to an REM suppressive effect. The results indicate that weak high-frequency electromagnetic fields have no effects on nocturnal hormone secretion except for a slight elevation in cortisol production which is transient, pointing to an adaptation of the organism to the stimulus.

Human sleep EEG under the influence of pulsed radio frequency electromagnetic fields. Results from polysomnographies using submaximal high power flux densities

Former exploratory investigations of sleep alterations due to global system for mobile communications (GSM) signals have shown a hypnotic and REM-suppressive effect under field exposure. This effect was observed in a first study using a power flux density of 0.5 W/m2, and the same trend occurred in a second study with a power flux density of 0.2 W/m2. For the present study, we applied a submaximal power flux density of 50 W/m2. To investigate putative effects of radio frequency electromagnetic fields (EMFs) of cellular GSM phones on human sleep EEG pattern, all-night polysomnographies of 20 healthy male subjects both with and without exposure to a circularly polarized EMF (900 MHz, pulsed with a frequency of 217 Hz, pulse duration 577 μs) were recorded. The results showed no significant effect of the field application either on conventional sleep parameters or on sleep EEG power spectra.

Reoperations for persistent and recurrent secondary hyperparathyroidism.

Forty-nine rcoperations for persistent or recurrent secondary hyperparathyroidism (HPT) in 30 patients are reported. The patients are part of a total of 184 patients operated on for secondary HPT; 28 reoperations in 18 patients were performed in the neck or in the upper mediastinum for remaining glands. Eleven reoperations at the forearm autograft revealed hyper-plasia of the grafted tissue as the reason for recurrent disease in seven patients; they were treated by excision of all grossly enlarged particles. Ten patients received autologous cryopre-served tissue because of permanent postoperative hypopara-thyroidism. The rate of graft-dependent recurrent HPT was 7%, and inadequate graft function was found in 6% of the patients.

A confirmatory study on the mechanisms behind reduced P300 waves in depression

A single-trial analysis of event-related potentials (P300) of 21 depressives was performed in comparison with matched controls. The purpose was to confirm previous results revealing an overall reduction of the single-trial P300 amplitude in depression despite fewer elicited single-trial P300 waves in schizophrenics. The result of the present study is in line with our previous investigation implicating a general reduced P300 amplitude on single trials of depressive patients. Therefore, it appears possible to differentiate depressives and schizophrenics by measuring event-related potentials and applying a single-trial analysis of them.

A replication study on P300 single trial analysis in schizophrenia: confirmation of a reduced number of ‘true positive’ P300 waves

A single trial analysis of event-related potentials (auditory odd-ball paradigm) of 20 schizophrenics was performed in comparison to matched healthy controls. The purpose of the study was to test the hypothesis that in schizophrenia the well-known P300 amplitude reduction of averaged event-related potentials is due to fewer elicited single trial P300 waves. The results of the present study support this finding of our previous exploratory investigation and point to the view that schizophrenics reveal basal disturbances in information processing due to inadequately elicited electrophysiological responses to target stimuli.

Amplitude frequency characteristics of evoked potentials during sleep : An analysis of the brain's transfer properties in depression

Classical analysis of the spontaneous sleep EEG in depressive disorder commonly reveals alterations of sleep continuity, number of awakenings, slow-wave sleep, and REM sleep compared to healthy controls; however, conventional analysis can not help understand dynamic differences of the sleep EEG during different sleep stages. In order to elicit qualitative alterations of information processing between depressives and healthy controls, we measured late components of auditory and visual evoked potentials (AEPs and VEPs) during different sleep stages of 15 depressive inpatients and in a sex- and age-matched control group from scalp positions Fz, Cz and Pz. According to linear system theory, we then computed the amplitude frequency characteristic (AFC) from averaged AEPs and VEPs in different sleep stages. These AFCs describe the input/output relation of the system under study leading to a characterization of the transfer properties of the brain during sleep in depression. Our investigations showed that information processing appears characteristically altered in depression during non-REM sleep for both auditory and visual stimulation compared to healthy controls. The transfer properties for processing auditory as well as visual information during REM sleep do not appear dynamically impaired in depressive disorder.

An analysis of the brain's transfer properties in schizophrenia: Amplitude frequency characteristics and evoked potentials during sleep

BACKGROUND Classical analysis of spontaneous sleep electroencephalogram (EEG) in schizophrenia commonly reveals alterations of sleep continuity, number of awakenings, slow-wave sleep (SWS), and REM sleep compared to healthy controls; however, conventional analysis cannot help understand dynamic differences of the sleep EEG during different sleep stages. METHODS We measured late components of auditory evoked potentials (AEPs) and visual evoked potentials (VEPs) during different sleep stages of 11 schizophrenic inpatients and in a sex- and age-matched control group from scalp positions FZ, CZ, and PZ. According to linear system theory, we then computed the amplitude-frequency characteristic (AFC) from averaged AEPs and VEPs in different sleep stages. These AFCs describe the input-output relation of the system under study, leading to a characterization of the transfer properties of the schizophrenic brain during sleep. RESULTS Significant differences could be found for the transfer properties during stage II and SWS between schizophrenics and controls. During REM a marked enhancement of theta resonance was seen in schizophrenics. CONCLUSIONS The results of the present study point to highly different central nervous system transfer properties in schizophrenics and controls. Compared to previous investigations in depression, the results provide additional information for distinguishing schizophrenia and depression in EEG studies.

Electrophysiological evidence for an inverse benzodiazepine receptor agonist in panic disorder

Inverse agonists of the GABA(A) receptor clearly decrease the amplitudes of the spontaneous EEG in the beta-frequency range. Therefore, we tested the hypothesis that panic patients exhibit a reduction of the EEGs spectral power in the beta-frequency band. Ten unmedicated patients with panic disorder and agoraphobia according to DSM-III-R criteria and 10 matched controls were investigated under baseline conditions, after hyperventilation and 30 min after hyperventilation. EEG recordings from the position Pz and Cz were performed under eyes closed conditions. At baseline conditions the patients suffering from panic disorder depicted a reduced beta-power reaching statistically significance for lead position Pz. Immediately after hyperventilation for both channels we observed a decreased beta-power. After hyperventilation we observed the same situation as under baseline conditions. Taken together, our results point to the view that in panic disorder an endogenous inverse agonist of the GABA(A)-benzodiazepine receptor could be hypothesized.

Effekt von Calcium und Magnesium auf die Parathormonfreisetzung aus humanem Parathyreoidea-Gewebe in vitro

SummaryThe effects of calcium and magnesium on parathyroid hormone release from eight adenomas causing primary hyperparathyroidism and six hyperplastic glands causing hypercalcemic secondary hyperparathyroidism were investigated in vitro using single cell suspensions from the respective tissue. We observed suppression of parathyroid hormone release with increasing concentrations of either cation. The quantitative hormone secretions of both adenomatous and hyperplastic glands was identical.The effects of calcium and magnesium on parathyroid hormone release from eight adenomas causing primary hyperparathyroidism and six hyperplastic glands causing hypercalcemic secondary hyperparathyroidism were investigated in vitro using single cell suspensions from the respective tissue. We observed suppression of parathyroid hormone release with increasing concentrations of either cation. The quantitative hormone secretions of both adenomatous and hyperplastic glands was identical.